Changes in the isotype composition of beta-tubulin delivered to regenerating sensory axons by slow axonal transport
Changes in the isotype composition of beta-tubulin delivered to regenerating sensory axons by slow axonal transport
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DOI：
10.1016/s0006-8993(96)00980-8
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发表时间：
1996-12-02
期刊：
影响因子：
2.9
通讯作者：
Luduena, RF
中科院分区：
文献类型：
--
作者：
Hoffman, PN;Luduena, RF
β-微管蛋白由在神经元中产生至少五种不同多肽同种型的基因家族编码。这些同种型中的两种（即，类LI和III）优先在轴突中积累，并且它们之一（即，II类）与发育和再生过程中的轴突生长密切相关。在背根神经节（DRG）神经元中，II类同种型的表达在出生后早期发育期间下降至相对低的水平，并且在轴突再生期间在成熟神经元中显著增加（即，达到与发育中的神经元相当的水平）。相反，LII类同种型的表达在出生后再生过程中略有上升。我们现在的文件，这些基因表达的变化与II类β-微管蛋白的相对量的增加相比，III类β-微管蛋白通过缓慢的轴突运输传递到再生的大鼠坐骨神经的感觉轴突。在这项研究中，在感觉轴突中转运的微管蛋白通过在坐骨神经破碎后7或14天将[S-35]蛋氨酸注射到L5 DRG中来标记;使用免疫沉淀法鉴定脉冲标记的II类和III类β-微管蛋白。在再生轴突中运输的β-微管蛋白的同种型组成的这种变化可能通过改变轴突微管的组装和动力学特性来影响生长。
beta-Tubulin is encoded by a family of genes that produces at least five distinct polypeptide isotypes in neurons. Two of these isotypes (i.e., classes LI and III) preferentially accumulate in axons, and the expression of one of them (i.e., class II) correlates closely with axonal outgrowth during development and regeneration. In dorsal root ganglion (DRG) neurons, expression of the class II isotype declines to relatively low levels during early postnatal development, and increases dramatically in mature neurons during axon regeneration (i.e., to a level comparable to that in developing neurons). In contrast, expression of the class LII isotype, which rises slightly during postnatal regeneration. We now document that these changes in gene expression are associated with an increase in the relative amount of class Il as compared to class III beta-tubulin delivered to regenerating sensory axons of rat sciatic nerve by slow axonal transport. In this study, the tubulin transported in sensory axons was labeled by injecting [S-35]methionine into the L5 DRG either 7 or 14 days after crushing the sciatic nerve; pulse-labeled class ii and class III beta-tubulin were identified using immunoprecipitation. This change in the isotype composition of beta-tubulin transported in regenerating axons may influence outgrowth by altering the assembly and dynamic properties of axonal microtubules..